Gel Leisure Batteries

[quickweh]

Can anyone offer advice on how to check the condition of gel leisure batteries? My problem is that the batteries are fully charged (13.8V) at the end of the day by the solar panels but by the morning they show 12.5V and very quickly discharge down to 11.4 when blown air heating and TV are switched on , approximately 5 amp current draw. The batteries are 2 120 Ah Banner units which should give more than the one hour I got this morning. :'(

[hallii]

I did mine by using a headlight bulb across the batteries one at a time (out of the M/H).

 

A 55w bulb gives a load of about 4.4 amps ( 55w / 12.5v) so one battery should, in theory, last for 27 hours.

 

It is a bit more complicated than that though, it is best to discharge the battery to no more than, say 11.75 volts, My estimate is that one of your batteries should give at least 10 hours with a headlight bulb, this would take the voltage down to about 11.75v.

 

It is a fairly inaccurate test but it will tell you how good or bad you batteries are.

 

From what you ahve said my guess is that one or both are well past thier best.

 

Dig deep, buy the best, they will last a lot longer.

 

H

[Keithl]

Mike,

 

The 13.8v you are measuring at the end of the day is not the state of charge of your batteries but the output voltage of your solar panels. You will have to disconnect them and then leave for a minimum of an hour before measuring the voltage to check their state of charge.

And yes I agree they should last considerably longer than an hour.

 

Keith.

[Derek Uzzell]

quickweh - 2013-04-27 10:38 AM

 

Can anyone offer advice on how to check the condition of gel leisure batteries? My problem is that the batteries are fully charged (13.8V) at the end of the day by the solar panels but by the morning they show 12.5V and very quickly discharge down to 11.4 when blown air heating and TV are switched on , approximately 5 amp current draw. The batteries are 2 120 Ah Banner units which should give more than the one hour I got this morning. :'(

 

Are you sure your motorhome (presumably still a 2011 Vantage Neo) has Banner 120Ah gel batteries?

 

Banner does market a specialised 120Ah gel product

 

http://www.pro-umwelt.de/gel-batterie-120-ah-c20-p-337.html

 

but I think it more likely yours will be AGM type (which is what the Vantage website says). The usually-fitted Banner AGM 'leisure battery' would be the "Running Bull" and (I think) the largest capacity is 95/110Ah.

 

https://www.roadpro.co.uk/retail/product_list.aspx?prod=Banner+AGM+Batteries

 

As Keith has advised, measuring the voltage at a battery's terminals when the battery is being charged (eg. via solar panels) won't reveal a battery's condition, nor will it reveal a battery's charge-state once charging has stopped. Nor will measuring the voltage when a battery is on load (eg. when a TV and blown-air heater are running) necessarily prove whether the battery is in good condition.

 

A no-load voltage of 12.5V suggests that your batteries would be 75% charged. As you've got over 200Ah of potential capacity available, if an hour's worth of TV and heater usage discharges the batteries to the point where (after they have been given time to recover) the voltage has dropped to a no-load, measured at the battery-terminals 11.4V (essentially fully discharged) then you've got a problem.

 

(When it comes to checking a leisure-battery's power-supplying capability, the procedure will be the same for 'wet acid', AGM or gel types.)

[quickweh]

Thanks Derek, a quick look under the drivers seat confirms that they are indeed a Pair of Banner 90/110 AGM units. My solar panel controller is a CBE PRS240 controlling a pair of solar panels (80 and 100w) with the switch set to Gel. I have reset the switch and will now monitor the system over the next week. I assume that the Gel setting voltage is too low to fully charge the batteries. :$

[Clive]

The charging regime has to be correct for starters.

The discharge test using a 55 watt bulb is as good as any and is what I use to test my own elderly (20 years old) 6 volt Exide gel batteries. Rated at 170 AH and I stopped when I had taken out 150 AH. Not bad!

 

C.

 

[Derek Uzzell]

quickweh - 2013-04-28 5:37 PM

 

Thanks Derek, a quick look under the drivers seat confirms that they are indeed a Pair of Banner 90/110 AGM units. My solar panel controller is a CBE PRS240 controlling a pair of solar panels (80 and 100w) with the switch set to Gel. I have reset the switch and will now monitor the system over the next week. I assume that the Gel setting voltage is too low to fully charge the batteries. :$

 

The Roadpro website says about Banner AGM batteries that these "...should be charged at the same voltage as standard flooded / wet lead acid batteries". Roadpro also provides this advice file

 

https://www.roadpro.co.uk/images/pdfs/Banner%20Batteries%20Information.pdf

 

However, the charging advice given in the "Running Bull AGM" part of Banner's website is "Only use voltage-regulated chargers with an IU-characteristic and the AGM/GEL charging programme".

 

My Hobby motorhome's leisure-battery is a Banner AGM (replacing the original Exide gel battery) and I use the Hobby's on-board battery-charger's 'gel' setting. It has to be said though that, due to the way I operate the Hobby, the majority of the battery's charge comes from the vehicle's alternator that will use the same charging regimen as for the vehicle's 'wet acid' starter battery (as also happened with the replaced 'gel' battery of course).

 

When I fitted the Banner battery I asked Banner(UK) whether I should choose the motorhome's on-board charger's 'gel' or 'wet acid' setting to avoid potential damage to the AGM battery and was told that either should be OK. There's a lot of on-line discussion about how AGM batteries should be best charged. If you want from-the-horse's-mouth advice, I suggest you seek it from Banner(UK) Tel: 01889 571100

 

A battery-charger's 'gel' charging regimen will be more rigorous than a 'wet acid' one. Technical details of your PRS240 solar charge regulator are here

 

http://www.cbe.it/en/content/prs240

 

and you'll note that the maximum and maintenance voltages for the regulator's "Lead-Gel" setting are higher than for its "Lead-Acid" settiing - the opposite to the assumption you've made in your last posting.

 

Being born with one leg is quite different to having one leg suddenly fall off. In the former case it's a characteristic: in the latter case it's a problem. I'm not sure you actually have a problem with your batteries because I'm uncertain how you are measuring your batteries' voltage, and you have not said whether there is any difference in how your batteries are behaving now and what they were doing when you bought your Vantage Neo and between then and now.

 

Besides the heater, TV, water-pump and lights that will be placing a electrical demand on your Banner batteries, I believe you also have a 12V compressor fridge. It's stating the obvious that, if your motorhome is static for a long period and its solar panel output cannot keep pace with the 12V requirements of the heater, TV etc. then the batteries' charge will inevitably diminish.

 

What you seem to be saying in your original posting is that your batteries' 12.5V voltage falls to 11.4V after one hour of 5 Amps discharge. Using very rough science, 12.5V should represent a remaining capacity of some 140Ah for your two batteries, while 11.4V would indicate an around 15% charge-state and a remaing capacity of about 28Ah. Essentially, a 5A/1-hour load would have somehow caused your batteries to lose 112Ah-worth of capacity. If that's what's actually happening (rather than voltage readings being taken when the batteries are not in a similar off-load 'stabilised' state) then - as hallii guessed earlier - one or both of your batteries is probably on the way out.

 

This MotorHomeFacts thread discusses operating a Vantage Neo

 

http://www.motorhomefacts.com/ftopicp-898016.html

 

and I note that jeffgolding (who initiated the thread) says

 

"As the fridge is non gas I opted to have an 80 watt solar panel fitted, this is wired directly into the Sargeant management system and so far this year we have been hook up free as I have found that the two 110 amp batteries are still 11v plus even after a full seven days away, obviously the standard LED lighting and the efficient 15 inch Avtex TV ( all standard equiptment) have helped to achieve this."

 

Received wisdom is that seriously discharging leisure-batteries (ie. well into the 11Vs) is bad practice and, if that's what you've been doing regularly, one or both of your batteries may be failing by now.

 

As has already been advised, you can test your batteries' present capacity by disconnecting them and (for each battery separately) testing their discharge-rate via a headlight bulb.

[crinklystarfish]

Trying to assess the condition of a battery by reference to its voltage when it is / has recently been receiving current, or when it is supplying current (as per the conditions described in the op) is pretty much a waste of time.

 

How long do they last under real-world conditions? If you don't know because they've never let you down, you more than likely do not have a problem.

 

I personally don't use any kind of voltage-based monitor because, under real-world conditions, they are useless - unless they are primarily utilised as a form of entertainment / distraction.

 

If it aint broke, fix it until it is...

[quickweh]

Thanks Derek, I will reply in more detail when I have carried out the checks you recommend but here is a little more detail -:

What prompted my post was starting the Whale gas heater and Avtex TV on a cold morning (Last Saturday) and getting a low voltage warning on the TV screen and the Whale system shutting down. The voltage display indicating 11.5V. On Saturday switched the fridge off so that there was no demand overnight and yesterday morning put heater and TV on to check. Voltage display showed a similar drop off after about one hour. We only used the heater on the evenings for about one hour along with the TV. We have overwintered in Spain on EHU and there is no problem in warm weather and long daylight hours when off grid.

This may or may not be relevant, the batteries are protected by a pair of fuses and last year I found that one fuse had only the tip contacting the harness, the harness not being fully engaged with the retaining block. I thought that I had solved the problem of low battery capacity but last weekends events indicate that I still have a problem to solve.

So, following your advice I will fully charge my battery pack and get testing as advised and report back.

Many thanks.

[quickweh]

quickweh - 2013-04-29 10:04 AM

 

Thanks Derek, I will reply in more detail when I have carried out the checks you recommend but here is a little more detail -:

What prompted my post was starting the Whale gas heater and Avtex TV on a cold morning (Last Saturday) and getting a low voltage warning on the TV screen and the Whale system shutting down. The voltage display indicating 11.5V. On Saturday switched the fridge off so that there was no demand overnight and yesterday morning put heater and TV on to check. Voltage display showed a similar drop off after about one hour. We only used the heater on the evenings for about one hour along with the TV. We have overwintered in Spain on EHU and there is no problem in warm weather and long daylight hours when off grid.

This may or may not be relevant, the batteries are protected by a pair of fuses and last year I found that one fuse had only the tip contacting the harness, the harness not being fully engaged with the retaining block. I thought that I had solved the problem of low battery capacity but last weekends events indicate that I still have a problem to solve.

So, following your advice I will fully charge my battery pack and get testing as advised and report back.

Many thanks.

 

 

I have now tested each of the batteries as follows -: Charged the battery pack yesterday on mains and solar and then disconnected the batteries last night to avoid solar charge this morning. Measured the open circuit voltage across the battery terminals this morning at 13.2V and 13.15V. Applied a 4 amp load to each battery in turn, battery 1 ran or one hour, start voltage 12.7V after 30 minutes 12.65V, 60 minutes, 70 minutes 11.38V. Battery 2 , start voltage no load was 12.9V, 4 amp load 12.56V, after 30 minutes 12.61V, 60 minutes 12.46V , 65 minutes 11.41V. This effect of seeing the voltage "falling off a cliff" is exactly what I see when camping.

I have taken your advice and talked to Banner UK, they suggested that the figures pointed to incompletely charged batteries and that it would take up to 3 days to fully charge the batteries on a mains charger. I will try again in 3 days and hope that it is a charging issue, expensive if it is a battery failure.

 

[hallii]

Sounds like it will be expensive then, from what you say the batteries are U/S.

 

It is possible that they were not fully charged so it is worth a try to see if they will charge up a bit more.

 

I would bet a weeks pension that they have had it, even a half charged battery would do better than that, still, the messing around has given you time to get used to the inevitable expense!

 

I replaced one this year, I should have done the two I know, but one was still holding a full charge and given the cost of them I thought it worth taking the risk. Everything is fine so far, fingers crossed.

 

H

[Derek Uzzell]

I agree that the omens are not good.

 

As Mike's motorhome is a 2011 vehicle, if he has not already done so, it would be worthwhile him contacting Vantage about this just in case it's a known problem and whether (if the batteries prove to be duff) there's any possibility of the issue being dealt with under warranty.

[Keithl]

My other thought is that the on-board charger and solar panel are not fully charging the pair of batteries and hence they are always running at a near discharged state, hence their shortened life.

 

In Mike's first post he said that they where at 13.8v at the end of the day with solar panel still connected, I doubt this is a sufficiently high voltage to fully charge the pair. I would have expected that he would need to be up around 14.4v to achieve a full charge.

 

Please correct me if I am wrong but I think you need to invest in a good quality charger suitable for the size of your pair of batteries. I would suggest one of the larger CTEK chargers suitable for the 220 Ah (?) you have.

 

Keith.

[Derek Uzzell]

Mike has owned his Vantage Neo since 2011. His motorhome has two solar panels (80w and 100w) and a pair of the Banner 95ah/110ah AGM batteries that Vantage fits to its conversions.

 

The CBE solar charge regulator in Mike’s Neo has been set to its ‘gel’ setting that will provide a maximum voltage of 14.3V and a maintenance voltage of 13.8V (see link I provided earlier in this thread).

 

I don’t know what on-board battery-charger Vantage installs, but I’d guess it will provide a charging regimen appropriate for AGM batteries and (as Vantage offers a 2nd AGM battery as an option) have an adequate output. (It would be worth Mike checking what on-board charger his Neo has and whether it’s set to ‘gel’ or ‘wet-acid’.)

 

Mike said earlier “We have overwintered in Spain on EHU and there is no problem in warm weather and long daylight hours when off grid.” So his motorhome’s electrical system has apparently functioned OK in normal use since 2011, but suddenly no longer does so.

 

If Mike’s batteries are now heavily discharged (as the around 11.4V readings suggest), it will require a battery-charger with a fair output to recharge them quickly. And, to charge them to their maximum potential (assuming they are in good condition), will also require the charger to have a suitable charging regimen. However, if Mike takes one battery and charges it over the 3-day period recommended by Banner using a reasonable charger, it should end up pretty well charged. If testing then produces the same ‘crash’ to below 12V after one hour of 4A load, battery replacement would seem to be the only option.

 

Battery testing is described in Section 6 of this webpage:

 

http://www.batterystuff.com/kb/articles/battery-articles/battery-basics.html

 

Banner’s Technical Guide

 

http://www.bannerbatterien.com/banner/infocenter/ratgeber/index_en.php

 

has Terms of Guarantee on Page 21.

[quickweh]

Derek, just a small correction, last year at Easter we had the same problem on an MCC rally but I put it down to the standard 85W solar panel supplied by Vantage, the cold weather and the lack of daylight hours and solar elevation to run the 4A load of TV and Whale heater. I later fitted an additional 100W solar panel in an attempt to remedy this. All worked really well last summer (?) and I thought I had solved the problem.

The batteries have been on mains charge now for 24 hours and the green fully charged light is on on the CBE control panel. I will do the tests again next week, we are off out this weekend :-)

Looking at other posts on this thread I am getting the impression that AGM batteries take a long time to charge and even 180W of panel is not sufficient to charge them in our cold/cloudy/early springtime weather.

It may be better to fit good quality lead acid units that are capable of taking a quick charge to take advantage of the fitted solar panels.

Who would have thought a pair of leisure batteries have such complexity :-S

ps I think that the mains charger fitted by Vantage is a Sargent unit, there is no Lead / Gel option but must be suited to AGM, it is the standard supplied by Scot.

[Derek Uzzell]

This link refers to AGM batteries

 

http://batteryuniversity.com/learn/article/absorbent_glass_mat_agm

 

and you'll note the statement "The leading advantages are a charge that is up to five times faster than the flooded version, and the ability to deep cycle."

 

I can't tell you how much faster (or slower) it would be for your motorhome's system to charge, say, a Banner "Running Bull" AGM battery or a same-capacity Banner "Energy Bull" wet-acid battery but, if you have gained the impression that fitting wet-acid batteries, and switching your solar panel's charge-regulator to its 'Lead-acid" setting, will improve the charging speed, I don't see that happening. (Banner might be able to advise on this.)

 

For reliable testing, you really need to isolate your batteries from your motorhome's electrical system, charge each battery individually (and not via your motorhome's battery-charger) until it's holding at 12.8V/12.9V after several hours have passed since charging was stopped, and then see what happens when you apply a load to it. If necessary, see if a local battery specialist will carry out a load-test on your batteries for you.

 

Plainly you could fit wet-acid batteries instead of AGM ones (if the wet-acid batteries were 'maintenance-free, you'd only have to ensure they were vented outside your motorhome's living-area) and this would be a cheaper replacement approach. But, unless it can be established why your present batteries are behaving in the way they are, I'm not confident this would automatically solve your problem.

 

 

[Brian Kirby]

If the batteries are shot, they should not have failed so quickly. If they have, it may be that one always was a dud, and is dragging down the other. Possibly the reason why you began to suspect you needed the extra solar capacity.

 

Alternatively, it would appear they may have suffered "abuse". Very simply, either someting that should be re-charging them isn't doing so, or they have been allowed to become heavily discharged, and left in that state over time.

 

Before spending any money on replacements I think it would be wisest to eliminate the causes of failure, 'else you risk a repeat performance with the replacements. If it is merely that they have been too heavily discharged and then not re-charged almost immediately, it is only the pattern of use and maintnance that needs changing.

 

Otherwise, possibly a bad connection, or a blown fuse somewhere, may be preventing one of the sources achieving charge. If charging on mains is definitely working properly, that sill leaves the alternator charging circuit, and the solar panels. Do you know for a fact that both of these are, actually, putting charge into the batteries?

[quickweh]

Firstly, thanks Derek and Brian, please see update below. :-)

 

1) I contacted Banner who kindly agreed to test the batteries, it took 3 days!! The batteries were shot, a 10A load on their test rig gave 30 minutes of use on both units, not far off my findings. A big thank you to Banner who were very sympathetic and gave a good deal on a replacement pair.

 

2) I contacted Vantage to check the manufacturer of the mains battery charger and discovered that the default setting for my model year was "maintenance charge" (float) and not the 3 stage dynamic setting so there was no chance of the batteries being fully charged on mains from the time I collected the van. Two minutes with a screwdriver to change the setting and 14.4 volts on the replacement batteries. Needless to say this is not the case for current production. I checked with Banner who confirmed that this was almost certainly the cause because the mode of failure was identical for both batteries.

 

Big thanks to Banner and all contributors to this thread. (^)